Well, I can tell you where the bad parts *are.* All of this is based on the 3.5e PHB and DMG.
1. The upkeep section of the DMG. It is inconsistent with the prices of food and lodging in the PHB.
2. The spellcasting prices in the PHB are ridiculously exorbitant.
A man in adventuring attire walks into a temple of Pelor.
Priest: "Greetings to you. How fares Brother Anthony?"
Adventurer: "He decided to go visit family, so he's taking the long way back to town."
Priest: "Well then, how may I assist you in your spiritual needs?"
Adventurer: "I got into a little run-in with bandits on the way back from the dungeon, and I was hoping I could get one of those nice little Cure Serious Wounds spells that Anthony wields so well."
Priest: "I see, my child. We do request a donation for the service, to assist in the clergy's promotion of good and right."
Adventurer (pulls out $20 and drops it in the donation box). "Of course."
Priest: "While we thank you for your generosity, the needs of the ministry do require slightly more."
Adventurer (nods and drops $200 into the donation box). "Tough times, huh."
Priest (smiles patiently): "I'm afraid that we have to ask for $30,000 for this service."
Adventurer (scrunches up his face and pauses before speaking): "Isn't that a little steep? I've been traveling with Brother Anthony for quite some time, and I know for a fact that it doesn't take him more than 3 or 4 minutes of prayer to prepare that spell, and there aren't any special components that go into the casting either."
Priest (smiling): "Well of course we can offer a discount for the faithful who promote good in the world. Let's drop it to half, $15,000."
Adventurer: "So you're telling me that I can either go down to the dealership and buy that stallion I've had my eye on, or I can 'donate' that cash for 4 minutes of your morning prayer?"
Priest: "Well, the temple does have needs that must be attended to."
Adventurer steps outside and looks up towards the front of the building.
Priest: "What is the problem, child?"
Adventurer (scans the building casually): "I thought this was the temple of Pelor. I'm just checking to make sure I didn't accidentally walk into the temple to Olidamma."
Adventurer (stepping back inside): "Look Brother, no offense, but I think instead of paying that sort of hospital bill I'm going to head home and take a couple of days off with a good book and maybe splurge on a bottle of fine wine." (Musing to self while walking out the door) "...maybe I'll stop by the dealership on the way home."
3. The price of buildings starts too high and scales too slowly. $200,000 sounds a bit steep for a "simple house of 1 to 3 rooms," especially with what the average peasant makes. Even if you drop it to 25% for a 1-room cottage that needs some work, we're still looking at something that would be difficult for a peasant to afford. Some might say it's a reasonable price, but according to the upkeep rules, a peasant should only be making about $2,400 per year after upkeep--and that isn't including investing in livestock and other important business necessities a peasant might have.
Young peasant man with wife, children, 3 cows, 5 pigs, and a dozen goats in tow.
Real Estate Agent (gesturing to a slightly dilapidated 1-room cottage): "And so here we have it. An excellent value for $50,000."
Peasant (jaw drops): "Did you say $50,000? For this? The roof leaks! And...and...the stones are comin' loose!"
Agent: "I assure you, despite the slight maintenance needs, this cottage is well worth the market price."
Peasant: "I've bin workin' 10 years to save up!" He sputters, "I've brought 3 good cows! And...and pigs!"
Agent: "Well, that's a nice start, but--
Agent: "--it's going to run a bit more than $11,000 for a good home like this."
Peasant (wide-eyed and jaw agape): "We only makes $3,000 a year after upkeep! Nellie's bin sellin' 'er hair!"
Agent: "I'm sorry that's it's such a sacrifice for you but--"
Peasant (pointing to small, barefoot daughter): "Little Emmie ain't got no shoes!"
Agent (sighs): "Would you like to think about it for a while first?"
Peasant: "It's not e'en furnished!"
Agent (holds up iron pot): "It comes with this."
Peasant: "That's just a pot!"
Short-haired peasant wife whispers something in his ear.
Peasant: "Okay, 'premium cookware,' but I still can't pay it!"
Agent: "It does come with a garden."
Peasant (sputtering): "The soil ain't even black!"
Peasant (sighs and takes hold of the cow ropes): "Nellie, get the pigs, we'll hafta move back in with your brother."
Peasant (suddenly stops): "Honey, is your brother still in the clergy."
Peasant: "Go ahead and take the livestock back."
Peasant (turning back to agent): "Eh' there. What would you say if I offered coupons for a couple of Cure Serious Wounds?"
I also, personally, don't like the price of mercenaries scaling by level, but most of the NPC service prices are right.
What I'd really recommend though, is to go download this:www.rpgnow.com/product/64423/Ye-Olde-Sho...
After I ran across that, I stopped trying to adjust prices myself. Everything in that book is internally consistent, and it sticks with PHB prices as much as possible (except for things like spell-casting.)
If you don't like that, I'd recommend cutting the price of spellcasting down to 10% (not counting any costly components), with half price discounts for clerical magic from friendly temples. For real estate, maybe drop the price of houses in half and call it good. For upkeep, you'd want to try piecing together prices from the food and lodging section in the PHB equipment lists. Extravagant, for instance, ough to be at lest 1000 gp based on food and lodging prices (which are a bit high themselves).
Yeah, I like it to be believable. :-)